If a mentally retarded couple had a child, would it be mentally retarded?

i.e both parents are mentally retarded, the child born from them i.e offspring will also be born mentally retarded ?

answer is no.

in this case :

social institutions, marriage bureaus keep a database of mentally retarded children and those children suffering from down syndromehelp them in getting married because i feel their offspring will not benecessarily suffer from down syndrome i.e trisomy 21 as the down syndromeis not a genetic or heritidary disease.

the joy of becoming parents for both suffering from down syndrome willbe accepted universally.

of course it's genetic. However, it doesn't have to be hereditary. Question is, what will happen, when the cell will try to split 3 chromosomes 21 into 2 new cells. Usually triploid organisms do not produce gametes, so the question is whether people with Down syndrom are fertile?

I know. I meant, that triploid organisms are not fertile and I do not know, whether organism with only one extra chromosome will be fertile, because theoretically the production of gametes should be arrested.